1. Field of the Invention
The present invention relates to a pressure vessel having a control device for opening and closing of locking jaws mounted on a cover of the pressure vessel.
2. Description of Related Art
As shown in FIG. 7, a pressure cooking vessel as disclosed in published International Application 92/03090 comprises a cover (40), two jaws (41), a control button (42) and a container (43). Wherein the jaws (41) are diametrically opposite one another relative to the longitudinal axis of the vessel, and mounted on the cover (40) for radial movement displaced via the control button (42) which is mounted in the center of the cover (40) to move axially. The control button (42) has an engagement portion (421) which is formed at a lower end of the control button (42) and specially shaped to act on inclined surfaces (411) fixed to the jaws (41) in order to displace the jaws (41) radially during axial displacement of the control button (42). Thus an axial movement of the control button (42) is transformed into a radial displacement movement of the jaws (41) between a closing position and an opening position. When in the closing position, the jaws (41) tightly grip the peripheral edge of the container (43) in order to hermetically seal the vessel. Conversely, the jaws (41) can occupy an unlocking position permitting opening of the vessel.
With reference to FIGS. 8 to 10, another pressure vessel of U.S. Pat. No. 5,613,424 comprises a cover (60), a container (61) and a control device (50) including two jaws (51) and a control element (52). The jaws (51) are diametrically opposite one another relative to the longitudinal axis of the vessel, and mounted on the cover (60) for radial movement displacement. The control element (52) is fixed with a triangular member (521) movable in a radial direction perpendicular to the radial direction of movement of the jaws (51). When the control element (52) is pushed or pulled manually along the radial direction, flanks of the triangular member (521) are engaged on the jaws (51) to progressively displace the jaws (51) apart or disengage with the jaws (51) to let the jaws (51) grip the peripheral edge of the container (61 ) tightly.
However, the above described conventional pressure vessels have the following defects;
1. the structure of the control device for the conventional pressure vessel is too complicated, which leads to high production costs; PA1 2. as the control device for the conventional pressure vessel requires a series of pieces which are movable relative to one another, a jamming risk may be provoked, so that the reliability of operation of the controlling device is not ensured; PA1 3. the operation of the conventional pressure vessel requires a lot of physical effort from a user, which offers less operating safety and inconvenience from the ergonomic standpoint.
Therefore, it is an objective of the invention to provide a pressure vessel to mitigate and/or obviate the aforementioned problems.